GHAZNI, Afghanistan, Sept 4 (Reuters) - Taliban insurgents detonated two powerful truck bombs outside the office of Afghanistan's spy agency and a police compound in the central town of Ghazni on Thursday, killing 18 people and wounding around 150, the provincial governor said.

The attack, the biggest in recent weeks, comes days after the National Directorate of Security, the intelligence arm that is leading the fight against the insurgents, was targeted in the east.

Ghazni provincial governor Musa Khan Akbarzada said a team of 19 insurgents was involved in the attack which also targeted a quick reaction team housed in the police compound. The explosions which shattered windows in the town were followed by gunbattles with Afghan forces, he said.